The Shrimps travel to Stevenage for a match featuring the bottom two sides in the EFL.
Stevenage currently sit bottom of League Two with nine points from 15 matches so far, one point behind Morecambe.
Both sides go into the game on the back of midweek defeats with Morecambe losing to Forest Green Rovers and Stevenage beaten by a late goal at Swindon Town.
Bentley said: “It’s a massive game – we’re at the wrong end of the table.
“It’s a ‘must not lose’ game and it’s an early six-pointer because we don’t want the gap to be increasing even more.
“It’s a big game for both of us. There’s no sugar-coating it, we’re in a relegation battle at the moment.
“If we think we aren’t, then we can be one, two or three wins from getting out of the bottom position.
“It’s a chance to put some daylight between us and them.
“Although we’re only a third of the way through the season, we’re in a relegation battle and we need to accept that.”
With that in mind, the last thing Morecambe needed would be to miss their top scorer.
That is another obstacle in their path, however, with Lewis Alessandra suspended after being sent off for two bookings on Tuesday.
That potentially opens the door for Shaun Miller with Saturday likely to come too soon for A-Jay Leitch-Smith to return from injury.
“It’s a massive blow,” Bentley said of Alessandra’s absence.
“He’s been one of our best players, if not the best.
“He is suspended and we can’t do anything about it but it’s an opportunity for someone to stake their claim.”